[noun] someone who acts as assistant Synonyms:aide
[adjective] functioning in a subsidiary or supporting capacity; "the main library and its auxiliary branches" Synonyms:subsidiary, supplemental, supplementary
[adjective] relating to something that is added but is not essential; "an ancillary pump"; "an adjuvant discipline to forms of mysticism"; "The mind and emotions are auxilliary to each other" Synonyms:accessory, adjunct, ancillary, adjuvant, appurtenant, subsidiary